What Is the U.S. Senate?

Legislation. No bill becomes law unless the Senate passes it in the same form as the House. The Senate can originate any bill except one that raises revenue, which must start in the House, and it can amend House bills freely. Most of what the Senate does on the floor is legislative: appropriations bills that fund the government, the annual defense authorization, and the policy bills that reach it from committee. See How a Bill Becomes a Law.

Confirming nominees. The president appoints cabinet secretaries, ambassadors, agency heads, Supreme Court justices and every federal judge only “by and with the Advice and Consent of the Senate.” Confirmation requires a simple majority. The Senate processes hundreds of civilian nominations each Congress and thousands of military promotions, and since rule changes in 2013 and 2017 nominations can no longer be filibustered, so the majority party can confirm on its own.

Ratifying treaties. A treaty negotiated by the president binds the United States only if two-thirds of the senators present approve it. That threshold has killed treaties from the League of Nations in 1919 to several arms-control and human-rights agreements since, and presidents now often avoid it by using executive agreements instead.

Trying impeachments. The House impeaches; the Senate holds the trial and decides. Conviction requires two-thirds of the senators present and removes the official from office. The Chief Justice presides when a president is on trial. Four presidential impeachment trials have been held and none has ended in conviction. Who can be impeached is covered on the powers of Congress.

Two rarer duties. If no vice-presidential candidate wins a majority of the Electoral College, the Senate elects the vice president (it did so once, in 1837). And under the 25th Amendment, a new vice president nominated to fill a vacancy must be confirmed by a majority of both the Senate and the House.

Presiding officer. The Constitution makes the Vice President of the United States the President of the Senate, with a vote only to break ties (see the VP’s tie-breaking vote). The vice president rarely attends; the President pro tempore, or more often a junior senator of the majority, presides in routine sessions. The presiding officer has far less power than the Speaker of the House. The real scheduling authority is the Majority Leader, a position the Constitution never mentions and that only emerged in the 1920s.

Committees. Bills and nominations go first to one of the Senate’s 16 standing committees, whose chairs, all from the majority party, decide what gets a hearing and a vote. Committee work is where most bills die and where nominees are examined. See how committees work and who chairs each one.

Unanimous consent. Senate rules are slow enough that almost nothing would pass if they were followed to the letter. So the two leaders negotiate unanimous consent agreements that set the terms of debate, and a single senator’s objection, a “hold,” forces the majority to spend days of floor time on cloture votes instead. Senators also have the right of unlimited debate, which is the source of the filibuster.

Votes. Most questions are decided by a simple majority of those voting: 51 if all 100 are present. Cloture on legislation needs 60. Treaties, impeachment convictions, veto overrides, expulsions and constitutional amendments need 67. Roll-call votes are recorded by name; voice votes are not.

Because only a third of the chamber is up in any cycle, control of the Senate is decided by a small number of competitive races, not by the national vote. Which seats those are, what each party needs to net, and results as they come in are on the 2026 balance of power page. The senators whose terms end after this election are grouped on Senate term end dates, and the general election is counting down here.